      :example "(the) [nbar dog [s-obj you see]]"}
     head-first
     head-principle
+    head-mod
     (let [mod-subj (atom :top)
           mod-pred (atom :top)
           mod-prop (atom :top)
-          head-mod (atom :top)
           mod-aspect (atom :top)
           mod-tense (atom :top)
           head-subcat (atom {:1 {:cat :det}

                          :subcat {:2 {:top :top}
                                   :3 []}}})

   ;; "has seen a dog" : complement is semantic object.
   (let [obj-mod (atom :top)
         obj (atom {:mod obj-mod})]

                            :slash false
                            :cat :verb}}))

   ;; TODO: should be :mod :first, not just :mod.
   ;; "[h turn ] [c off]"
   (let [iobj-mod (atom :top)]
     (unify-check h32
